Triangle sound simulating device

ABSTRACT

A triangle sound simulating device to be employed in an electronic musical instrument is composed of a fundamental sound signal oscillator, at least one additional sound signal oscillator for generating an additional sound signal of lower frequency than that of the fundamental sound frequency, the output level of the additional sound signal being selected to be lower than the output level of the fundamental sound signal obtained from the fundamental sound signal oscillator, and a switching circuit of nonlinear characteristic which, upon reception of the output signals can create a difference frequency sound signal of a frequency equal to the difference between those of the output signals each time the switching circuit is switched.

United States Patent 72 Inventor Tsukas a Uba 3,141,919 7/1964 Mabuchi a4/1.01x Hamarnatsu-shi,Japln 3,325,578 6/1967 Park 84/ 1.01 [2]] Appl. No. 4,259 3,328,506 6/1967 Park 84/124 [22] Flled Jan. 20,- 1970 3,410,948 11/1968 lshibashi et al. 84/126 [45] Patented Nov. 2, 1971 3,417,189 12/1968 Kramer 84/1.11 [73] Asslgnee gfi zzifgtg i g fiiztw g fiz r: Primary Examiner-Milton O. Hirshfield Prior Jan 21 1969 p Assistant Examiner-U. Weldon y p' Attorney-Holman & Stern 31 44/4692 ABSTRACT: A triangle sound simulating device to be em- 54 TRIANGLE SOUND SIMULATING DEVICE ployed in an electronic musical instrument iS composedof a schimmznnwing 118$ fundamental sound s1gnal oscillator at least one additional sound slgnal osc1llator for generatmg an additional sound [52] US. Cl 84/1.0l, signal f lower frequency m that f the fundamemm sound 84/124 frequency, the output level of the additional sound signal [51] Int. Cl Gl0h 1/00 being selected to be lower than the output level f the f d [50] Field of Search 84/].01, mental Sound signal Obtained f the f d l sound signal oscillator, and a switching circuit of nonlinear characteristic which, upon reception of the output signals can create [56] References (med a difference frequency sound signal of a frequency equal to UNITED STATES PATENTS the difference between those of the output signals each time 2,570,701 10/1951 Martin 84/1.01 X the switching circuit is switched.

FUNDAMENTAL I SOUND GENERATOR 3 4 l l SWITCHING TONE-COLOR ClRCUlT CIRCUIT ADDITIONAL l 2 SOUND OSCILLATOR TRIANGLE SOUND SIMULATING DEVICE BACKGROUND OF INVENTION This invention relates to an electronic device for simulating the sounds generated from musical] triangles. In electronic musical instruments, by employing combinations of active circuit elements such as electron tubes and transistors and passive circuit elements such as resistors, capacitors, and inductors, various circuits are combined to constitute sound effect generators which simulate sounds of various kinds of natural musical instruments. Although it is comparatively easy to obtain electronic devices for simulating artificially, sounds generated from string musical instruments and wind instruments, the sounds of percussion instruments which are more complicated have not been successfully simulated with sufficient naturalness of auditory sensation.

. Conventional devices for simulating percussion instruments, more specifically the sound of a triangle, have been composed of merely a single oscillator and a tone-color circuit for shaping the output of the oscillator. However, because merely a fundamental frequency and some of the higher harmonics thereof are generated from the single oscillator, the sound thus simulated by such an arrangement of the circuit is too simple and lacks naturalness in auditory sensation, although the organization thereof is simple and thereby advantageous.

SUMMARY or "me; INVENTION Therefore, the primary object of the present invention is to provide a device for simulating the natural sound of a triangle whereby the above described drawbacks of the conventional sound simulating devices can be substantially eliminated.

Another object of the present invention is to provide a novel device for simulating the sound of a triangle which can generate a sound far closer to the natural sound of a triangle.

Still another object of the present invention is to provide a novel device for simulating the sound of a triangle which is simple in organization and can be easily produced. These and other objects of the present invention can be achieved by a novel device for simulating the sound of a triangle which comprises an oscillator for generating a fundamental sound signal, at least one additional sound oscillator for generating an additionalsound signal having a lower frequency than that of the fundamental sound signal, and a switching circuit of nonlinear characteristic which can receive all of the above mentioned fundamental and additional signals simultaneously and create sound signal having frequencies equal to the differences between the frequencies of these signals, the sound level of the additional sound signal being selected to be at a lower level than that of the fundamental sound signal.

The nature, principle, and utility of the present invention will be more clearly understood from the following detailed description with reference to the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING In the drawing:

FIG. 1 is a block diagram for an explanation of the principle of. the present invention; and FIG. 2 is an electric circuit diagram showing adevice for simulating the sound of a triangle, which constitutes a preferred embodiment of the present invention.

DETAILED DESCRIPTION Referring now to FIG. I which shows a basic concept of the present invention, the device shown comprises an oscillator l for generating a fundamental sound signal having a frequency f an additional sound oscillator 2 for generating an additional sound signal having a frequency j}. lower than the frequency f of the fundamental sound signal, a switching circuit 3, and a tone-color circuit 4. With the above described organization of the simulating device of a triangle sound, the output of the fundamental sound oscillator I of the frequency f and the output of the additional sound oscillator 2 of the frequency f, are mixed at an appropriate level ratio before entering a switching circuit 3 and the output thus obtained is applied to the tone-color circuit 4.

The switching circuit 3 is one having a nonlinear characteristic represented for example, by a curved gain, and may exhibit a saturation and a class C amplification as is inherent with such nonlinearly operated devices, a difference sound signal is produced by same having a frequency equal to the difference between f of the fundamental sound signal and f, of the additional sound signal. The switched output comprises this difference frequency sound signal, the above described fundamental sound signal, and the additional sound signal, these signals being mixed again and applied to the tone'color circuit 4 so that the natural sound of the triangle can be simulated. FIG. 2 illustrates a circuit diagram of a device simulating the sound of a triangle, which constitutes one embodiment of the present invention. In this circuit, there are provided a fundamental sound oscillator 1 including transistors Tr, and Tr an additional sound oscillator 2 including transistors Tr, and Tr a switching circuit 3 including a transistor Tr a resistor R,, and a capacitor 0,; and a tone-color circuit 4 including a capacitor C, and a resistor R The output signals from the oscillators l and 2 including a considerable amount of higher harmonics are reduced respectively to appropriate levels through series connected circuits, one of which consists of a resistor R and a capacitor C,, and the other of which consists of a resistor R, and a capacitor C, The signals thus reduced to suitable levels are then mixed at the input side of the switching circuit 3. In the switching circuit 3, the mixed signal is then applied to the base electrode of a transistor Tn.

When a switch S, inserted in the emitter circuit of the transistor Tr, is opened after it has been closed, the bias voltage of the transistor Tr, is varied in accordance with a time constant determined by a resistor R, and a capacitor C whereby the output signal passing through the switching circuit 3 is decayed.

At this time, because of the inherent nonlinear characteristic of the switching circuit 3, a difference frequency signal is created, so that as the output of the switching circuit 3, a mixed signal consisting of the above described two signals and the difference frequency signal can be obtained. When the output signal thus mixed is thereafter passed through the tone color circuit 4 consisting of a resistor R, and capacitor C a desired sound simulating a triangle can be obtained. As a result of various experiments, I have found that, when the frequencies f, and f, of the fundamental sound and the additional sound are 4 KI-lz and 1.35 kHz, respectively (difference frequency f,- ,=2.65 KI-Iz), and the mixing level ratio of the fundamental sound to the additional sound is 1:0.03, a sound creating an extremely natural auditory sensation of a triangle can be obtained. The preferable ranges of the fundamental sound frequency, the additional sound frequency and the mixing level ratio thereof are, respectively, from 3 kHz to 5 kHz, from 1 kHz to 2 kHz and from 120.02 to 1:0.04, and the fundamental sound frequency should not be of the just integer multiple of the additional sound frequency.

Although, in the embodiment described hereinbefore, merely a fundamental sound oscillator and an additional sound oscillator are employed, it will be apparent that more than two oscillators may also be employed in the circuit, and when the number of the oscillators are thus increased, a sound producing an even more natural sensation in simulating the sound of a triangle can be obtained.

Iclaim:

l. A triangle sound simulating device comprising a fundamental sound oscillator for generating a fundamental sound signal, at least one additional sound oscillator for generating an additional sound signal of lower frequency than that of the fundamental sound frequency, the output level of said additional sound signal being lower than the output level of said fundamental sound signal, means to mix said fundamental and 2. A triangle sound simulating device as defined in claim 1 wherein the output signal obtained from said switching circuit is further passed through a tone color circuit.

3. A triangle sound simulating device as defined in claim 1 wherein said switching circuit comprises a transistor and a switching means inserted in the emitter thereof, whereby each time the circuit is switched, a nonlinear characteristic is exhibited in the output of the transistor. 

1. A triangle sound simulating device comprising a fundamental sound oscillator for generating a fundamental sound signal, at least one additional sound oscillator for generating an additional sound signal of lower frequency than that of the fundamental sound frequency, the output level of said additional sound signal being lower than the output level of said fundamental sound signal, means to mix said fundamental and additional sound signals, and switching circuit means of nonlinear characteristic which, upon reception of said mixed signals from said fundamental and additional sound oscillators, switches said signals and generates a further sound signal of a frequency equal to the difference between those of said mixed signals at the time of the switching operation, the output of said switching means comprising said fundamental sound signal, said additional sound signal, and said frequency difference signal.
 2. A triangle sound simulating device as defined in claim 1 wherein the output signal obtained from said switching circuit is further passed through a tone color circuit.
 3. A triangle sound simulating device as defined in claim 1 wherein said switching circuit comprises a transistor and a switching means inserted in the emitter thereof, whereby each time the circuit is switched, a nonlinear characteristic is exhibited in the output of the transistor. 